1 //===-- sanitizer_win_weak_interception.cpp -------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // This module should be included in the sanitizer when it is implemented as a 9 // shared library on Windows (dll), in order to delegate the calls of weak 10 // functions to the implementation in the main executable when a strong 11 // definition is provided. 12 //===----------------------------------------------------------------------===// 13 14 #include "sanitizer_platform.h" 15 #if SANITIZER_WINDOWS && SANITIZER_DYNAMIC 16 #include "sanitizer_win_weak_interception.h" 17 #include "sanitizer_allocator_interface.h" 18 #include "sanitizer_interface_internal.h" 19 #include "sanitizer_win_defs.h" 20 #include "interception/interception.h" 21 22 extern "C" { 23 void *WINAPI GetModuleHandleA(const char *module_name); 24 void abort(); 25 } 26 27 namespace __sanitizer { 28 // Try to get a pointer to real_function in the main module and override 29 // dll_function with that pointer. If the function isn't found, nothing changes. 30 int interceptWhenPossible(uptr dll_function, const char *real_function) { 31 uptr real = __interception::InternalGetProcAddress( 32 (void *)GetModuleHandleA(0), real_function); 33 if (real && !__interception::OverrideFunction((uptr)dll_function, real, 0)) 34 abort(); 35 return 0; 36 } 37 } // namespace __sanitizer 38 39 // Declare weak hooks. 40 extern "C" { 41 void __sanitizer_on_print(const char *str); 42 void __sanitizer_weak_hook_memcmp(uptr called_pc, const void *s1, 43 const void *s2, uptr n, int result); 44 void __sanitizer_weak_hook_strcmp(uptr called_pc, const char *s1, 45 const char *s2, int result); 46 void __sanitizer_weak_hook_strncmp(uptr called_pc, const char *s1, 47 const char *s2, uptr n, int result); 48 void __sanitizer_weak_hook_strstr(uptr called_pc, const char *s1, 49 const char *s2, char *result); 50 } 51 52 // Include Sanitizer Common interface. 53 #define INTERFACE_FUNCTION(Name) 54 #define INTERFACE_WEAK_FUNCTION(Name) INTERCEPT_SANITIZER_WEAK_FUNCTION(Name) 55 #include "sanitizer_common_interface.inc" 56 57 #pragma section(".WEAK$A", read) 58 #pragma section(".WEAK$Z", read) 59 60 typedef void (*InterceptCB)(); 61 extern "C" { 62 __declspec(allocate(".WEAK$A")) InterceptCB __start_weak_list; 63 __declspec(allocate(".WEAK$Z")) InterceptCB __stop_weak_list; 64 } 65 66 static int weak_intercept_init() { 67 static bool flag = false; 68 // weak_interception_init is expected to be called by only one thread. 69 if (flag) return 0; 70 flag = true; 71 72 for (InterceptCB *it = &__start_weak_list; it < &__stop_weak_list; ++it) 73 if (*it) 74 (*it)(); 75 76 // In DLLs, the callbacks are expected to return 0, 77 // otherwise CRT initialization fails. 78 return 0; 79 } 80 81 #pragma section(".CRT$XIB", long, read) 82 __declspec(allocate(".CRT$XIB")) int (*__weak_intercept_preinit)() = 83 weak_intercept_init; 84 85 static void WINAPI weak_intercept_thread_init(void *mod, unsigned long reason, 86 void *reserved) { 87 if (reason == /*DLL_PROCESS_ATTACH=*/1) weak_intercept_init(); 88 } 89 90 #pragma section(".CRT$XLAB", long, read) 91 __declspec(allocate(".CRT$XLAB")) void(WINAPI *__weak_intercept_tls_init)( 92 void *, unsigned long, void *) = weak_intercept_thread_init; 93 94 #endif // SANITIZER_WINDOWS && SANITIZER_DYNAMIC 95